Pakistani tribal families flee their villages, passing through the Khyber area, on Tuesday, April 12, in Pakistan. Violent clashes continue in Tirah Valley of tribal areas in Pakistan, which started eight days ago, when militants belonging to the Lashkar-e-Islam clashed with local Zakhakhel tribe killing many people.

Two US drone strikes reportedly killed six suspected militants Wednesday in South Waziristan, a move that is likely to incense Pakistani officials who had just a day earlier disclosed their demand for a halt to all drone strikes.

It was the first drone attack since the March 17 strikes that killed up to 44 people, including a large number of civilians, CNN reported. The scale of that strike prompted unusually strong condemnation from Pakistani military officials.

A security official in South Waziristan told Reuters that two drones fired four missiles on a vehicle carrying militants. "We have confirmation of six [killed] but toll could be high," the official said.

The drone program has been controversial since it got under way almost seven years ago. Continuing it, even if it is a critical component of the US counterterrorism campaign, is likely to only exacerbate an already strained US-Pakistan relationship, highlighted by yesterday's demands for an end to drone strikes and a drawdown in the number of CIA and Special Forces operatives working in the country.

Mr. Davis, a CIA contractor working in the country under the guise of being a low-level US embassy employee, shot and killed two Pakistani men who he claimed were trying to rob him. Davis is believed to have been in the country to gather information on the Pakistani militant group Lashkar-e-Taiba.

"In the long term, it [the drone attacks] is completely counter-productive because it alienates the population and restricts our ability to shape our security environment," the official said, adding that Pakistan is now pushing back against US demands that they launch an offensive in North Waziristan.

"What do they [the US] want us to do? Declare war on our whole country?" the official said.

Although antidrone sentiment is on the rise, the attacks seem to be occurring at a much lower rate this year – the Los Angeles Times tallied 19 so far in 2011, compared with 117 last year.

The Los Angeles Times also reports that prior to the March 17 attack, Pakistan's military acknowledged the drones' effectiveness in combating the militants, saying that most of the people killed in the attacks were militants, not civilians.

“Above all, what they’re annoyed about and motivated by is the sense that they don’t know what’s going on in their own country,” Mr. Weinbaum said. “If they’ve decided to play harder ball now, it’s because they feel they have some leverage to change a situation they don’t like.”